When Andrew Chan and Myuran Sukumaran arrived at Bail's notorious Kerobokan prison almost 10 years ago, they were known to the outside world as the "godfather" and the "enforcer" of the Bali nine drug smugglers.

But to prison volunteer Lizzie Love, a former maths and science teacher at Bankstown High, they were "just regular western suburbs Sydney kids".

"It was just quick money. They didn't even think about the consequences," she says of the busted attempt to smuggle more than eight kilograms of heroin - with a Sydney street value of $4 million - into Australia.

"They wanted to do it for the women and the money and the glamour. It was just typical rear brain teenage thinking."

In jail they call Love Dadong Bule, Indonesian for white granny. It amuses her; she's hardly a sweet granny. Love is one of the founding members of the Lipstick Brigade – an offshoot of the Bali International Women's Association who preferred to get their manicured nails dirty volunteering at the jail rather than win door prizes at luncheons. Their help at the jail was appreciated; once the female guards wore red lippy in their honour.

It is feisty, altruistic ladies such as Love, and other expats and Indonesians who volunteer at Kerobokan prison who have born witness to the transformation of Sukumaran and Chan and the prison itself.

Ten years ago the BengKer, or prison industry workshop in Kerobokan prison, was used as a "furniture" factory. Stories of methamphetamines and other pills being smuggled out in sticks of furniture were legion.

"I understood it was pretty much a meth lab in there," Love says. "If you were out on the town and had ears and listened to someone who wanted an eca [ecstasy] they'd say 'Hang on, we'll run up to the jail' and they'd throw them over the wall and put them on the account. And if the account wasn't paid you'd get a pen in the neck."

Andrew Chan teaches computer skills to inmates.

Chan and Sukumaran were shocked by the depravity of the drug use. "When they got in there they got to see all the people sticking their needles in their arms every day and on the shabu shabu (crystal meth) pipes and they really understood how rotten their crime was," Love says. "And they were ashamed of it. They realised they had shamed their countries and their mothers. Myuran said to me: 'I have to make up for this. I am going to spend the rest of my life in here but I am going to fix this'."

The day Love met Sukumaran in 2007 she was delivering 160 mattresses to the jail. "All of these women were sleeping on cement on sarongs with piles of clothing for pillows." Sukumaran helped unload the mattresses. "He's a big guy … when I first saw him I thought: 'Oooh, he's a bit menacing'."

Love looks and talks like a flamboyant artist, but she still has the brisk, no-nonsense manner from her teaching days at Bankstown High. "I said: 'How the hell do I spell your name … don't worry I'll google it. He said: 'Don't google it, you'll see all these bad things about me'.

"I said: 'As far as I'm concerned, I know you are Bali nine, and had something to do with drugs but I don't want to know anything else.'"

Sukumaran told Love that documentary makers visited the prison all the time. When it was over he never saw them again. "It feels like being dumped," Sukumaran told her. "I said: 'I'll make an agreement to come back'."

The worst time to be in Kerobokan prison is during the sticky months of December, January and February. "The tension in there fluctuates with the weather - and Christmas and Ramadan is always a volatile time, with emotions running high," Love says. "There is a lot of violence in that prison especially at night when they are all locked away."

Simmering hostilities are exacerbated by ennui. In the early days of Chan and Sukumaran's incarceration, there were few activities for the women in Block W. "They were so starved of anything to do. The women would just lie on their beds. They had no idea of what day it was - it was miserable," Love says.

Sukumaran was concerned they were becoming institutionalised. He approached Love and asked if she could teach a co-ed beginner art class in the library. A mixed-sex activity was unprecedented and it took some time for the prison governor to approve a 26-week course. Guards watched over the classes to make sure there was no unsolicited behaviour.

"As time went by they saw I was a strict school maam - we didn't allow any jiggy-jig," Love says.

The course couldn't have been more basic; how to wash brushes, blue and yellow makes green. "It was really beginning stuff, but I've never in my life had students that attentive. Pretty soon we started to see paintings go up on the wall of their cells, even primitive paint by numbers stuff. The walls started to take on a less institutionalised look."

The popular and reformist prison governor, Pak Siswanto, saw the merit in the classes and allowed other activities to be held. Sukumaran organised computer graphics and sewing lessons. Inmates used their newfound skills to establish a T-shirt printing business in the BengKer.

Chan, whose family used to own a restaurant, ran cooking classes. "The little cooking class became a really good business - all the guards were buying it," Love says. Another Australian, Jocelyn Johinke, taught a reflexology class. Again, the guards were the guinea pigs. Graduates of the class were able to earn money giving head and shoulder massages. One former inmate was even able to pay for her child's schooling.

Si Yi Chen, another member of the Bali nine, started a silver making studio, drolly named Mule Jewels. Inmates learn a trade skill - silversmiths are highly sought after in Bali - and escape the toxic and overcrowded cell blocks. Love says the boys are supported by "lovely, compassionate prison guards - people who want some stability in there. The BengKer became an oasis from the cesspool".

Chan has trained to become a pastor in Kerobokan. He studied through Harvest Bible College in Melbourne, submitting assignments via snail mail or visitors to the prison. Chan was a man on a mission. Lecturers were amazed when he refused offers of extensions during even the grimmest periods, such as when the Indonesian president rejected his clemency plea.

"Andrew does a lot of the pastoral care - basically he's the social worker in there," says Gayle Dwije, a pastor at C3 Church in Bali. Dwije, an Australian who has lived in Bali for 20 years, has known Chan and Sukumaran since 2006. Her husband Wayan established Yayasan Tangan Kasih Indonesia (Arms of Love Indonesia), a Christian charity that "exists to bring hope to a hurting world" and oversees projects in Kerobokan prison.

"The prison was very different in those days. It was very basic - the visiting area was a dirt garden. It was very hot, with no shade - just a bit of cement in the ground." There were dark days, days of depression in the early years, Dwije recalls. But in the last six to seven years both men have been positive, galvanised into making amends to their families, the Indonesian people and society more broadly.

Kerobokan prison may have improved over the past 10 years but it's still a harsh place for inmates without money or families. Prisoners have to pay for supplementary food to the meagre supplies and toiletries. "Andrew said the women really need some hygiene packs," Dwije says. So Arms of Love helped him assemble packs of things we take for granted; toothpaste, sanitary products, earplugs. Chan and the prison governor handed out the packs together. "In the last two years they have been brought in for both the men and the women," Dwije says.

Sukumaran has been nicknamed the gentle giant. He is often described as philosophical, his gentle voice belying his imposing stature. But in some ways he can still be an enforcer. One thing that causes his temper to flare is prisoners using drugs. He has a zero tolerance approach to drugs in the BengKer, although he has also been known to accept recovering addicts if they are on the methadone program.

Love says if she has had battles with Sukumaran, they have been over his uncompromising response to drug users in the jail. "I would try to teach him to try to deal with it intellectually not physically … he's mellowed on that somewhat," she says.

As macabre as it sounds, there is already jockeying over who will take over the BengKer. Some prisoners are terrified. Chan and Sukumaran had an uncompromising stance against drugs. Sukumaran is such a zealot he won't even take valium to ease the sleepless nights. Without the Australians' influence, many fear the prison workshop will once again become the domain of the drug overlords.

"They want the territory and it's frightening and Myuran kept them out," Love says. "You can feel the tension building. I don't even know how to explain it. It's like you can cut the air."

Sukumaran is beginning to talk about the executions. He says he is going to be taken into a field and shot and if he doesn't die in three minutes he will be shot in the head. The uncertainty, the wait, his family's anguish are all taking their toll. Sukumaran's vitiligo, a chronic skin disease where patches of skin lose their pigment, is getting worse. Sukumaran is embarrassed by it, but no amount of the coconut oil that visitors bring to the jail will get rid of it. "I think the stress has made it worse," says Tina Bailey, who teaches art and dance in the jail. "It's all started since being in prison."

Chen is also feeling the strain.

"He's processing it deeply, he's thinking about it, he's concerned about them," Bailey says. "His hope is that all the people Andrew and Myuran have helped and all those helped in his silver studio will not return to jail. That is his goal."

Sukumaran is an avid reader. He's borrowed Love's collection of art books and recently told Bailey to read Tuesdays with Morrie, Mitch Albom's memoir about conversations with a dying man. He's also reading Houses of Healing: A Prisoner's Guide to Inner Power and Freedom.

"This is a book about the whole process of what happens in prisons when they become houses of healing," Bailey says. "When you involve art and you build a person ... you allow them to sometimes develop in ways that society has denied them."

A female prison guard, who has worked at Kerobokan prison for more than 20 years, told Bailey: "In the early years this was just a prison, now it's a rehabilitation centre. It makes coming to work much easier."

This is what most saddens and frustrates all those who have come to know Sukumaran and Chan. The waste of two lives. Men who are making a profound difference within a once notorious jail.

Love recently sent flowers to the prison guards, who she says are also distressed. "The bottom line is for many guards it is like a family in there. They're feeling the loss. They wouldn't let me use the word execution."

Jewel Topsfield is the national correspondent for The Age and Sydney Morning Herald, based in Melbourne. She was previously the Indonesia correspondent. She has won multiple awards, including a Walkley for international journalism and the Lowy Institute Media Award.